[Solved] How does source code manage white space and concatenation [duplicate]

Don’t break the string up like that unless you use . to concatenate them back together!

So, either:

 $email_body = 
   "message from $name \n 
   email address $visitor_email \n
   \n $message"; // also the whole string on one line is fine

or

$email_body = 
   "message from $name \n" 
   . "email address $visitor_email \n"
   . "\n $message";